First off, it's based on an accounting identity! God I love the government:

Qnfb = ALaK1-a

(this is my crudely typed version of equation 3 in the CBO document)

Sadly they forgot the third bar in the equal sign. This is an accounting identity! A is TFP which is defined as what's left over in output after we impute the effects of labor and capital (the CBO freely admits this by the way). a is assumed to be 0.30 and constant over time.

Potential labor and potential TFP are forecasted by piecewise linear regressions where the breakpoints ARE NOT DETERMINED BY ANY SORT OF STATISTICAL CRITERION (again, read the document if you doubt me).

The CBO method is arbitrary and weak. Defending it via appeal to authority by saying "it's based on the Solow model" is pathetic.

Second, the measure of potential output is crucially dependent on all the forecasting assumptions used to produce potential Labor and potential TFP, which are not based on any real economic theory or optimal statistical algorithm.

Finally, the CBO itself says things that are remarkably Bullard-like right in the document Duy links to:

"CBO's framework explicitly models the factors that determine the accumulation of capital, so the projection for the capital stock is fully consistent with CBO's projections for private saving and the federal budget. Specifically, a higher projected rate of saving will lead to faster accumulation of capital and faster growth of potential output. Therefore, a higher projected federal surplus, which generally raises

the rate of national saving, will speed up the growth of the capital stock and potential output in the model. Conversely, a recession or other event that depresses the saving rate will temporarily slow the accumulation of capital and the growth of potential output."

That's right, according to the CBO, federal deficits lower the path of potential output! It must be true, after all, it's based on the Solow model.